1. Field of the Invention
The present invention relates generally to peripheral equipment for use with an electronic apparatus and, particularly, to a card-type peripheral device, suitably used in a detachable manner, for a small-sized portable electronic apparatus.
2. Description of the Related Art
In peripheral equipment usable for small-sized portable electronic apparatuses, such as a notebook-size personal computer, a digital camera and so on, a card-type peripheral device that can be detachably attached to the housing of the electronic apparatus has been known. Also, various types of card-type peripheral devices acting as memories, interfaces, etc. are available. A typical card-type peripheral device is formed by assembling a circuit board carrying electronic parts thereon, a connector for connecting the circuit board with a certain objective apparatus, and a hollow, card-shaped housing for accommodating therein the circuit board and the connector.
Conventionally, a card-type peripheral device is provided with various countermeasures for noise, such as a provision of an electrically conductive material for the housing, in order to protect the internal circuitry from external noise, such as electromagnetic waves or static electricity, as well as to suppress the radiation of electromagnetic waves from the internal circuitry. Particularly, in the card-type peripheral device generically called a PC card or a PCMCIA card, it has been standard to form a ground terminal at a predetermined position on the outer periphery of the card-shaped housing, the ground terminal serving to connect ground conductors or lines on the circuit board with the ground of an objective apparatus body.
In a typical conventional PC card with noise control measures, the housing is constituted from a rectangular frame for supporting the circuit board and the connector, and a pair of upper and lower, electrically conductive panels fitted to the frame to cover the front and back sides of the circuit board. The conductive panels are electrically connected to the ground conductors on the circuit board via contact elements, which have resilience and electrical conductivity, such as compression coil springs or leaf springs. Further, an electrically conductive clip is attached to a predetermined position of the frame, and is soldered to the ground conductor of the circuit board, so that the ground terminal is formed at a predetermined position on the outer periphery of the housing. When the noise control measures are to be enhanced, electrical conductivity is imparted not only to the panels but also to the frame.
As described above, the typical conventional PC card uses some additional components for noise control measures, i.e., the contact elements for connecting the ground conductors on the circuit board to the panels, and the clip for forming the ground terminal at a predetermined position of the frame. These additional components are generally very small, and thus make the operation for soldering these components onto the circuit board to incorporate them in the frame and the panels troublesome. In particular, skilful work is required for ensuring the positional precision of the components. As a result, and due to the increased number of components, the manufacturing cost of the PC card tends to increase.
It is therefore an object of the present invention to provide a card-type peripheral device including a frame for supporting a circuit board and an electrically conductive panel fitted to the frame, the card-type peripheral device also being provided with proper and stable noise control measures which can be easily made at a relatively low cost without using any additional component.
In order to accomplish the above objects, the present invention provides a card-type peripheral device comprising a circuit board having a ground conductor; a conductive frame for supporting the circuit board; and a conductive panel attached to the conductive frame and cooperating with the conductive frame to surround the circuit board; wherein the conductive frame includes a frame section having an exposed surface portion, a first contact section formed integrally with the frame section and making electrically conductive contact with the ground conductor of the circuit board, and a second contact section formed integrally with the frame section and making electrically conductive contact with the conductive panel.
In this card-type peripheral device, it is preferred that the first contact section exhibits a spring action.
The frame section of the conductive frame may be provided with a board receptacle for receiving the circuit board, and the first contact section may be formed in the board receptacle.
The first contact section may include a resiliently deformable arm integrally joined at a proximal end thereof with the frame section and a projection as a contact point integrally protruding from a distal end of the arm.
It is advantageous that the conductive frame further includes an engaging section formed on the frame section adjacent to the first contact section, the engaging section cooperating with the first contact section to hold the circuit board at a predetermined position.
It is also preferred that the second contact section exhibits spring action.
The frame section of the conductive frame may be provided with a panel receptacle for receiving the conductive panel, and the second contact section may be formed in the panel receptacle.
The second contact section may include a resiliently deformable arm integrally joined at a proximal end thereof with the frame section and a projection as a contact point integrally protruding from a distal end of the arm.
The frame section of the conductive frame may be provided with a slit for receiving an engaging piece formed on the conductive panel, and the second contact section may be formed in the slit.
The frame section of the conductive frame may be provided with a recess for receiving an extension formed on the conductive panel, the extension serving as a visually distinguishable ground terminal.
The first contact section may be constituted as a plurality of first contact sections respectively formed integrally with the frame section, and the second contact section may be structured as a plurality of second contact sections respectively formed integrally with the frame section.
The conductive panel may be constituted as a pair of conductive panels respectively arranged on opposite sides of the conductive frame, the pair of conductive panels being electrically connected with each other when the conductive panels are assembled together on the conductive frame.
The card-type peripheral device may further comprise a connector incorporated in the card-type peripheral device for an electrical connection of the circuit board.
The conductive frame may be integrally molded from an electrically conductive resinous material.